LAGOS Analysis

Loading in data

First download and then specifically grab the locus (or site lat longs)

# #Lagos download script
LAGOSNE::lagosne_get(dest_folder = LAGOSNE:::lagos_path())

#Load in lagos
lagos <- lagosne_load()

#Grab the lake centroid info
lake_centers <- lagos$locus

Convert to spatial data

#Look at the column names
#names(lake_centers)

#Look at the structure
#str(lake_centers)

#View the full dataset
#View(lake_centers %>% slice(1:100))

#st_as_sf, takes table and makes into spatial objects
spatial_lakes <- st_as_sf(lake_centers,coords=c('nhd_long','nhd_lat'),
                          crs=4326) %>% #crs is projection system. diff codes
                          st_transform(2163) #transforming projection for map view

#Subset for plotting
subset_spatial <- spatial_lakes %>%
  slice(1:100) 

subset_baser <- spatial_lakes[1:100,]

#Dynamic mapviewer
mapview(subset_spatial)

Subset to only Minnesota

states <- us_states()

#Plot all the states to check if they loaded
#mapview(states)
minnesota <- states %>%
  filter(name == 'Minnesota') %>%
  st_transform(2163)

#Subset lakes based on spatial position
minnesota_lakes <- spatial_lakes[minnesota,]

#Plotting the first 1000 lakes
minnesota_lakes %>%
  arrange(-lake_area_ha) %>%
    slice(1:1000) %>%
  mapview(.,zcol = 'lake_area_ha')

In-Class work

1) Show a map outline of Iowa and Illinois (similar to Minnesota map upstream)

#filtering out the states of interest
Iowa <- states %>%
  filter(name == 'Iowa') %>%
  st_transform(2163)

Illinois <- states %>%
  filter(name == 'Illinois') %>%
  st_transform(2163)

#combining the two states and mapping them
maps <- rbind(Iowa,Illinois)
mapview(maps)

2) Subset LAGOS data to these sites, how many sites are in Illinois and Iowa combined? How does this compare to Minnesota?

iowa_lakes<-spatial_lakes[Iowa,]

illinois_lakes <- spatial_lakes[Illinois,]

A: There are 4,644 lakes in Iowa, and 11,822 lakes in Illinois for a combined total of 16,466 lakes. Minnesota has 29,038 lakes, almost double the amount in Iowa and Illinois.

3) What is the distribution of lake size in Iowa vs. Minnesota?

  • Here I want to see a histogram plot with lake size on x-axis and frequency on y axis (check out geom_histogram)
iowa_size <- iowa_lakes %>%
  ggplot(aes(x=lake_area_ha))+
  geom_histogram(bins=20,
                 fill="cadetblue3",
                 color= "lightblue3",
                 alpha=0.5)+
  scale_x_log10()+
  theme_few()+
  labs(x= 'Area (ha)', y= 'Count',title="Iowa Lake Size Histogram")

illinois_size <- illinois_lakes %>%
  ggplot(aes(x=lake_area_ha))+
  geom_histogram(bins=20,
                 fill="cadetblue3",
                 color= "lightblue3",
                 alpha=0.5)+
  scale_x_log10()+
  theme_few()+
  labs(x= 'Area (ha)', y= 'Count',title="Illinois Lake Size Histogram")

ggarrange(iowa_size,illinois_size, ncol=1, nrow=2)

4) Make an interactive plot of lakes in Iowa and Illinois and color them by lake area in hectares

Iowa_Illinois_lakes <- rbind(iowa_lakes,illinois_lakes) 

Iowa_Illinois_lakes %>%
  arrange(-lake_area_ha) %>%
  slice(1:1000) %>%
  mapview(.,zcol='lake_area_ha')

5) What other data sources might we use to understand how reservoirs and natural lakes vary in size in these three states?

A: A dataset with lake inflows and outflows would be beneficial in understanding how much water moves through the system and could potentially bypass remote sensing for maximum and average depth.